Induction Hardening Coil Control for Uniform Austenitization

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Inductive hardening processes face challenges in achieving uniform temperature distribution and minimizing temperature inconsistencies in components, leading to potential structural issues and reduced service life.

Innovation Solution

An inductive hardening system and method that control heat input through a control unit, adjusting current strength, voltage, frequency, and coupling distance to introduce a first maximum heat input followed by a reduced heat input, ensuring uniform temperature distribution before quenching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a high heat input is applied to heat the component above austenitization temperature, then the hardening effect is improved, but temperature inconsistencies and non-uniform microstructure transformation occur

Engineering Contradiction:

Improveaustenitization temperatureVSAvoidtemperature uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by continuously moving the induction coil relative to the component during the hardening process. This dynamic approach ensures that heat is distributed more uniformly across the component surface, preventing localized overheating and temperature inconsistencies while maintaining the necessary austenitization temperature for hardening.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs periodic action through oscillating or reciprocating motion of the induction coil relative to the component. This periodic movement allows for controlled heating cycles that promote uniform temperature distribution and consistent microstructure transformation throughout the hardened region.

Inventive Principle:

Principle #19Periodic action

2Speed

If the component is cooled quickly to martensite temperature, then the hardening speed is improved, but temperature inconsistencies and non-uniform transformation from austenite to martensite occur

Engineering Contradiction:

Improvecooling speedVSAvoidmicrostructure uniformity

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent applies dynamics during the cooling phase by maintaining continuous relative motion between the induction coil and component. This dynamic cooling approach ensures uniform heat extraction and promotes consistent austenite-to-martensite transformation throughout the component, preventing localized transformation inconsistencies even at high cooling speeds.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent maintains continuity of useful action by keeping the induction coil in continuous contact or close proximity to the component throughout both heating and cooling phases. This continuous presence ensures uniform thermal action during the critical transformation period, promoting consistent microstructure development despite rapid cooling.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If the induction coil is stationary and heats a fixed region, then the heating process is simple, but temperature inconsistencies occur due to localized overheating

Engineering Contradiction:

Improvecoil movement mechanismVSAvoidtemperature distribution uniformity

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The patent resolves this contradiction by implementing dynamic movement of the induction coil relative to the component. This movement distributes the thermal energy more evenly across the target region, eliminating localized overheating and achieving uniform temperature distribution without requiring complex multi-coil arrangements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces movement in the spatial dimension, transforming the heating process from a static, localized application to a dynamic, distributed application. This dimensional change allows a single induction coil to effectively treat a larger area uniformly, avoiding the need for multiple stationary coils while maintaining temperature uniformity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces temperature inconsistencies, optimizes residual stress distribution, and enhances the uniformity of the hardened zone, reducing the risk of cracking and warpage while improving the service life of components.

Implementation Method 1

the induction coil is designed to induce an electric current in the component and thus to achieve a defined heat input in the component

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a current is induced in the component that leads to a heating of the component

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20230220512A1Induction hardening system and induction hardening method

Publication Date: 2023.07.13 AB SKF SKF PATENT DEPARTMENT

AI summary

An inductive hardening system for hardening a component includes a holding unit for holding the component, an induction coil configured to induce an electrical current in the component to heat the component, and a control unit configured to control the induction coil to produce a first amount of heat per unit area in the component until a predetermined temperature is reached and/or a predetermined time is elapsed and after the predetermined temperature is reached and/or the predetermined time is elapsed, to control the induction coil to produce a second amount of heat per unit area in the component, the second amount of heat being from 3% to 80% of the first amount of heat.